Teko S3O Organic Merino Heavyweight Hike Socks (Charcoal, Small) merino-wool Superfine Merino wool fibers dry & evaporate moisture quickly, MERINOfiber regulates your temperature Anatomical fit - smooth, seamless & snug Performs best in cold, wet and damp conditions Extremely durable Ultralight/Light/Medium* IMPAX Zoned Cushioning System for optimum comfort, Lifetime tekoFITGuarantee